NSIS Error launching installer

First my already installed flux disappeared. I tried to open it, but it said it was missing some files. So I unistalled it and tried to install from the same file I successfully used before -- no luck. Newly dowloaded installers had the same problem. I followed every advice on the web for NSIS error, nothing helped. I don't have problems installing any other apps. So is there a way to install f.lux again?